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Objective: Peritoneal dialysis(PD) is one of the most important clinicalmethods to improve azotemia and to correct fluid balance disorder forEnd-stage renal disease(ESRD) patients. Volume control is essential toguatantee that peritoneal dialysis could run smoothly for a long period, whichpredicts outcome in patients with residual renal function(RRF) together.Volume overload is related to hypertention, left ventricular hypertrophy,cardiac dysfunction, malnutrition-inflammation and ultimately increasedmortality. In contrast, hypohydration is known to cause ischemiccardio-cerebrovascular disease and loss of residual renal function. Theconsequence of volume depletion let some clinicians to run their patientsslightly ‘wet’ with the aim of protecting residual renal function. Evidence infavor of this derives from the clinical observation that increased ultrafiltrationled to decreased residual urine output. Based on this, this study applymultifrequency bioimpedance analysis to evaluate volume status in PDpatients and intend to intervere their fluid status, for the purpose ofinvestigating wheter volume status influenced residual renal function and itsrelationship between cardiovascular system.The whole point to all this ishoping to reduce mortality rates in PD patients.Methods:67patients on peritoneal dialysis in The Third Hospital,Hebei medical university between July2013and Febrary2014were includedif they were older than18, less than70and PD vintage was over than3months. All patients were evaluated overhydration(OH) by Bio-impedanceanalysis(BIA) during the routine clinical examination. Meanwhile,demographic, biochemical and clinical data, such as the nephritic primarydisease, dialysis complications or endocardiography parameters, were alsorecorded. Mearurement of overhydration: BCM（Body Composition Monitor，theFresenius Medical Care, Germany), employed the bioimpedance spectroscopy,is used to assess individual volume status and body composition in PDpatients. BCM measures extracelluar water(ECW) and total body water(TBW),then OH value is calculated automatically via internal formulas. Electrodeswere attached to one hand and one foot at the ipsilateral side, after the patienthad been in recumbent position for at least10minutes without touching anymetal object. According to the OH value, our study analyze the relationshipbetween volume status, cardiovascular system and residual renal function.For another research purpose, patients mentioned above who wereanuric(weekly urine Kt/V＜0.1and daily urine output＜200ml) and onintermittent peritoneal dialysis(IPD) at baseline were excluded.32continuousambulatory peritoneal dialysis(CAPD) patients were finally enrolled. All thesepatients, who have accepted the PD prescription adjustment, had BCMmeasurement and biochemical data been recorded at baseline and6monthslater(follow-up). Patients were divided into two groups: overhydration andnon-overhydration. Comparision were used to explore wheter there is astatistical difference in loss of RRF between two groups and to determine therelationship between volume status and RRF.Statistical analysis: Continuous data are expressed as mean±standarddeviation. Categorical data are expressed as percentage of total. Comparisonbetween groups used student’s t-test, Mann Whitney U-test and chi-square test.Pearson correlation and Spearman correlation were used to bivariate analysis.The regression model was created based on variables that had a simplecorrelation of P＜0.05with OH. All statistical significance were taken as P＜0.05and analysis were done by SPSS18.0.Results:1. A total of67patients were included. Average time on PD was15.10±13.41months and mean OH was3.26±2.22L. In this population,65.7%were fluid overload (vs euvolemia,4.32±2.00vs1.23±0.62L). Therewas no statistical difference in age, weight, height, BMI, PD vintage, PDmodality and peritoneal transport status. Males (vs females,3.99±2.46vs 2.35±1.47L, P=0.002) tend to have higher OH.2. The cross-section: Of all patients,61.2%had the sign of heart failure,13.4%among which were euvolemia who account for7.4%,6.0%,0%,0%respectively in NYHA class1,2,3,4and account for7.5%exist left ventricularhypertrophy. Patients with heart failure in fluid overload were about47.8%,and7.4%、17.9%、18.0%、4.5%respectively in NYHA class1,2,3,4. Nostatistical difference in RRF between two groups. The simple correlationanalysis showed variables that positive correlated with OH included SBP, DBP,MAP, LVMI, NYHA class(r=0.37,0.29,0.22,0.37,0.63，P＜0.05) and thatnegative correlated with OH were ALB, Hb, total Kt/V(r=-0.33,-0.35,-0.27，P＜0.05). But when the patient who was anuric (r Kt/V=0) was excluded, wefound a negative relation between OH and RRF(r=-0.35,-0.27，P＜0.05).After multivariable linear regression analysis, variables remained significantassociated with OH only included age, gender, NYHA class, total Kt/V, Hband ALB.3. Simple correlation analysis of perspective research: There is a positiverelation between the change of RRF and baseline urine Kt/V, baseline SBP,baseline MAP(r=0.685,0.36,0.366, P＜0.001), but no correlation withoverhydration. After patients were divided into two groups according to OHvalue, we still found no significant difference between them in the change ofRRF.Conclusion: It is necessary that we should take precautions against fluidoverload in PD patients. Volume status is independently related to age, gender,weekly total Kt/V, hemoglobin and albumin. Furthermore, there is noprotection or reduction in residual renal function whether fluid is overload ornot, and the negative effects of overhydration such as left ventricularhypertrophy and cardiac dysfunction will lead to a poor life quality andsurvival of dialysis.
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